Range-finder.



' No. 742,038. PATENTED 00120. 1903*. J. W. KERN, DEGD.

v s. u. KERR, ADMINISTBAIBIX.

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J. W KERN, DEGD S. M. KERN, ADMINISTRATBIX.

PATENTED OCT. 20, 1903.

RANGE FINDER.

APPLICATION FILED MAY 16, 1901.

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No. 742,038. PATENTED OCT. 20,1903

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RANGE FINDER.

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UNiTED STATES Patented October 20, 1903.

PATENT OFFICE.

SAR-ATH M. KERN, or PORTLAND, OREGON, ADMINISTRATRIX or JOHN W.

- KERN, DECEASED.

RANGE-Fl NbEFlt' SPECIFICATION forming part of Letters Patent N 0.742,038, dated October 20, 1903.

I Application filed May 16, 1901.

To a whom, it may concern:

Be it known that I, SARAH M. KERN, a citizen of the United States,residing at Port land, in the county of Multnornah and State 3 ofOregon, am' the administratrix of the estate of JOHN W. KERN, deceased,late a citizen of the United States, who invented certain new and usefulImprovements in Range- Finders; and I do hereby declare the follow-' ingto be a full, clear, and exact description of-the invention, such aswill enable others skilled in the art to which it appertains to formultiplying the distance traversed by the movable end of the movabletelescope it would '65 notbe possible to determine accurately by theslight movement of the pointer the distance make and use the same.

The invention has for its object to provide I5 simple and effectivemeans whereby in a certain and ready manner to ascertain the distance ofan object from the point, of observation or to locate a point at adesired distance from that of observation.

2o Briefly stated, the invention comprises two telescopes, one of which,at least, must be pivotally mounted to permit its being moved at anangle with relation to the second telescope in order that bothtelescopes may be focused upon a common distant object. Combined withthe movable telescope and operatively connected therewith to receivemovement therefrom is a hand or pointer adapted to be moved overthe'graduated surface of a dis-' 3o tance-indicator, and the mechanisminterme diate the distance-pointer and the movable telescope is soproportioned and arranged that when the pivoted telescope is moved fromits initial position and brought to a focus upon a distant objectpreviously brought within the focus of the stationary telescope thedistance-pointer will be so moved from its initial position withrelation to the pivoted telescope as instantaneously to indicate 40 uponthe distance-dial the remoteness from.

the finder of theobject sighted.

In the one embodiment. of the invention shown a bed-plate carrying twotelescopes is employed, one of the telescopes being rigidly fixed on thebed-plate and at-exact right angles to its base-line and the othernormally parallel with the first-named telescope, but adapted forpivotal movement on the bed plate to permit adjustment to bring an ob-5o ject seen through the fixed telescope into the range of the movabletelescope, a graduated Serial No. 60,605. (No model.)

dial bearing distan ce-marks suitably arranged thereon,"a' pointer totraverse the dial, and

motion-transmitting mechanism connecting the movable telescope and thepointer, where- 5 5 by the movement of the movable telescope willactuate the pointer to indicate on the dial the distance of therange-finder from the object under observation.

The adjustment of the movable telescope 6o will of necessity be veryslight in sighting objects at long rangesay from one to five miles-sothat without the provision of means measured. To provide forthis,suitable means are provided-in the present instance amicrometer-screw, which is operatively connected, respectively, with themovable telescope g'and with the pointer. The micrometer-screw referredto comprises two screws or worms on a single shaft or bar, the screwcoacting with the movable telescope having, say, one hundred threads tothe inch and that coact ing with the pointer ten threads to the inch.

Thus a movement of the telescope through the arc of a circle of oneone-hundredth of an inch will cause movement of the pointer 8c throughan arc of a circle of several inches,

thereby permitting'the distance-marks onthe .dial to be widely spacedapart, and thus rendered easy to read.

In combination with the base-plate there may be suitable mechanism forelevating, depressing, and rocking the plate laterally andlongitudinally and in addition a tangent-screw, by which arrangement thedevice will be adapted for use as a transit or surveyors instrument inrunning 0 lines, determining distances, or for other purposes in whichthe ordinary theodolite is employed. When used as a transit ortheodolite, a suit-able tripod will be provided, and, if desired, acompass may be combined with 5 the bed-plate,

When used as a range-finder pure and simple, the elevating, depressing,and tilting mechanism mentioned and hereinafter to be fully described issuitable when the instrn- 10ov ment is employed in connection withmilitary operationsthat is, for finding the range for artillery upon theland. When, however, the finder is to be used at sea, the motion of thevessel renders that mechanism inefficient, so that the same ora partthereof may be dispensed with and the base-plate supported upon aswinging or universal joint and be so counterweighted as to remainconstantly in a level position irrespective of the rolling or pitchingof the vessel. One finder may be provided for a group of guns upon theship, or, if preferred, each gun may be furnished with a separatefinder. In the latter instance the finder may be mounted upon the turretor carriage of the gun, with the fixed telescope pointed in a directionexactly parallel with the line of fire, so that when that telescope isfocused upon the object and the range has been determined by means ofthe movable telescope and its attendant mechanism it will only benecessary to elevate the barrel of the gun in order to give the desiredtrajectory to the projectile.

One of the important advantages of this invention is that by providing abed-plate or other support with two telescopes, each mounted on thebed-plate or support and arranged in sufficient proximity to each otherto permit of being rapidly operated by a single operator, thetransmission of telephonic signals or audible signals, such as areusually necessary in the employment of rangefinders now in use, isobviated.

Before proceeding with the description of the device it may be noted atthis point that in the practical application of the principles embodiedin this invention to a working machine the known ratios of expansion andcontraction between different metals employed in its construction willbe observed, so that errors in calculation which might arise were theknowledge of these ratios not observed will be prevented.

In the accompanying drawings, forming a part of this specification, andin which like letters of reference indicate corresponding parts, thereis illustrated a form of embodiment of the invention in which it isshown as adapted for use as a range-finder for vessels and also forsurveying purposes, it being understood that the same ideas may becarried into effect in connection with other forms of device withoutdeparting from the spirit of the same.

In the drawings, Figure l is a view in plan of a device when used eitheras a transit or as a range-finder, exhibiting the bed-plate,indicating-dial, and telescopes. Fig. 2 is a similar view with the dialremoved, exhibiting the mechanism by which motion -may be imparted tothe pointer. Fig. 3 is a view in elevation taken from the right-handside of the machine and looking in the direction of the arrow 1 in Fig.2. Fig. 4 is a view in elevation looking in the direction of the arrow2, Fig. 2. Fig. 5 is a view in elevation of a part of the device lookingin the direction of the arrow 3, Fig. 2. Fig. 6 is a horizontalsectional view of the elevating, depressing, and swinging mechanism,taken on the line 4 4, Fig. 5. Fig. 7 is a sectional detail view of atangent-screw by which fine adjustment of the bed-plate may be effectedin the running of lines or the like.

Referring to the drawings, A designates generally the bed-plate, whichmay, as shown, be an open-work structure made of any suitable material,such as iron, aluminium, brass, or any other material suited to thepurpose. This bed-plate may be mounted in any suitable position foroperation, as upon the carriage of a gun or in the port-hole of a vesselor upon a tripod, the latter being employed where the device is used forsurveying puroses.

While the device herein shown is not exhibited as associated with acompass, it is to be understood that the same may be employed where thedevice will be used for running lines in landwork.

The bed-plate A is provided on its upper surface with two levels a aarranged at right angles to each other, these being used when the deviceis employed for surveying purposes and may, if desired, be omitted whenthe device is used as a range-finder, as it will be obvious thatanyleveling of the deviceindependent of the vessel will be impracticableon the high seas. Upon the u pper side of the bed-plate are mounted twotelescopes B and B the telescope B being rigid with relation to thebed-plate and arranged exactly at right angles to its base-line or rearedge and the telescope 13 being mounted for pivotal movement at itsfront end upon the bed-plate and being moved at its rear end throughmechanism hereinafter to be described. The telescopes are, as usual,provided with suitable cross-wires by which to center an object and withadjustable lens, as will be understood. Adjacent to the fixed telescopeBand in line with each other are arranged two standards or initialdirection-finders I), each comprising a rod of metal having its upperend polished or burnished, by which to present an object readilyattractive to the eye.

Each of the telescopes B and B is supported upon a suitable casting bthis casting in the case of the movable telescope B being pivotallysecured at its forward end to the bedplate or casting A. The rear end ofthe casting of telescope B is provided with a bearing 11 comprising aframe b and a pivoted block b capable of swinging laterally and formedwith a threaded opening adapted to be engaged by the threads on one endof a rod 1). Mounted also upon the bed-plate and between the telescopes,preferably in close proximity to the movable telescope B is a circularcasing D, having a dial (Z laid off in requisite divisions, as feet,yards, and miles, these being arranged upon a series of concentriccircles, as shown in Fig. 1. Pivotally mounted upon the side of thecasing or upon the bed-plate immediately adjacent thereto is asector-wheel 0, having a long arm 0 extendingwithin the casing'and ashort arm without the casing, the latter arm being provided with atoothed edge 0, these teeth being engaged by a wormgear upon the rod 19Mounted centrally within the casing is a pointer or hand d carried bythe shank of the pinion d mounted in bearings 61 beneath the dial, thepinion being engaged by the toothed portion 0 of the long arm 0 of thesector-wheel. Theindicating-handofthepointer d is provided with an openportion d in which is secured a Wire d arranged radially to traverse theconcentric'circles of the dial. The threads upon the rod b, engaging thebearing b will in this instance be one hundred to the inch, and thethreads of the worm engaging the sector-teeth 0 will be, say, ten to theinch, and the relative lengths of the respective arms of thesector-wheel will be so proportioned that by the movement of the movabletelescope a distance of one one-hundredth of an inch under the action ofthe twisting motion given to the rod 11 the pointer 61 will be caused tomove through an are upon the dial of ten inches, by which multiplicationof movement the reading of the measurements ascertained will be rendered clear and easy. 7

To prevent backlash or any jarring of the hand or pointer d the pinion dmeshes with a gear-wheel 01 the pivots of which are mounted in asuitable casting d also beneath the dial, a coiled spring d secured atone end to the supporting-plate of the wheel d as shown in dotted linesat d and at the other end of the stud of the wheel, serving to take upany lost motion or play that would exist between the teeth of the piniond and the toothed sector 0, thereby causing the pointer 01 always totraverse the dial in a steady and regular manner.

As'shown in'Figpl, the dial is marked off into five concentric circles,which are divided 011' in divisions of feet, yards, and miles, as willbe understood by reference to the said figure. The arm a of the sector 0carries a vertical pin or pointer 0 which projects through a curved slot0 in the dial, the wall of this slot being laid off in divisions from 1to 6, these divisions corresponding to the circles on the dial.Initially or when an observation is to be taken the pointer 61 and 0will point, respectively, at the zero-mark on the large dial and on thecurved slot 0 When the pointer d is moved by the micrometer-screwthrough the arc of alarge circle, the pointer 0 will be moved throughthe arc of a smaller circle. The function of the pointer and its scale,which will be hereinafter referred to as a scale-indicator, is todetermine which circle on the large dial is to be inspected to determinethe reading. Thus,

for instance, ifthe small pointer is between 0 and 1 the reading will befound on the outer or first circle; if between 1 and 2 the reading willbe on the second circle,

and it between 2 and 3 the reading will be on the third circle, and soon. In

practice all readings from a greater distance than twelve hundred feetwill be found on the firstor outer circle.

The circular micrometer-head E, carried by the rod b, to which it issecured by the milled thumb-nut E',has its periphery marked 06 into asuitablenumber of divisions, preferably one hundred, as shown, to form ascale for reading the fraction of revolution of the rod'b. Secured bymeans of a bracket upon the bed-plate and cooperating with themicrometer-head E is a segmental scale e, forming a vernier and markedoff in this instance into ten divisions, these tendivisions beingexactly equal to nine of the divisions upon the micrometer-head E, thuspermitting a reading to one-tenth of the latter divisions. When thepointer upon the large dial has been brought to the zero-point, the nutE is loosened to permit the head E to be turned upon the rod 12 in orderto bring the zeropoint upon said head and upon the vernierscale intoregistry, when said nut is screwed down to secure the head to the rodand may then be used to turn the rod in finding the range.

The micrometer-threads being a distance of one one-hundredth of an inchapart, the scale E permitting a reading of one onehundredth of thisdistance and the vernierscale allowinga reading to one-tenth of adivision of the scale E, it will be seen that the movement of thetelescope B of one onehundred thousandth of an inch may be read,

so that the angular changes caused thereby while very small are easilyread.

The object of the micrometer-head E and vernier-scale e is to locate apoint at adesired distance from that of observationthat is to say,should it be desired to locate a point at one mile or farther from theoperator this disk and scale will then come into use, the marks on themicrometer-head and vernierscale indicating the micrometerscrew reading.Thus should it be desired to locate'a point five miles distant, or eightthousand eight hundred yards on the dial, the screw will be moved untilit indicates 21.96. Then by sighting the telescopes'to bring thecross-wires to bear upon a point at that'distance five miles will belocated: If it be desired to locate a point, say, three miles distant,or five thousand two hundred and eighty yards on the dial, the screwwill be moved untilitindicates 36.6. Then by sighting the telescopes tobring the cross-Wires to bear upon apoint at that distance three mileswill be located. If it be desired to locate apoint, say, four thousandyards distant on the dial, the screw will be moved until it indicates48.31. bring the cross-wires to bear upon a point at that distancefourthousand yards will be located. Secured to the under side of thebed-plate are brackets F,sh own provided witli Then by sighting thetelescopes to journal-bearings supported on journals car ried by astandard f. The standard f is provided at its lower end with a ball f(shown in dotted lines in Fig. 5,) engaging a ballsocket G, carried bythe base-support g. A four-arm spider g is supported on levelingscrews ghaving each their lower end provided with a ball engaging a ball-socketin the basesupport. The spider is mounted to turn on the standard, butis held from longitudinal movement thereon, as by shoulders on thestandard. A collarf closely fits the standard f and carries a set-screwf for looking it thereto. A tangent-screwfflshown carried on the spiderg engages said collar, thus providing precise means for adjusting thebed-plate in an arc about a vertical axis. To one of the brackets F isattached a graduated sector arranged to be traversed by the pointercarried by an arm a depending from the adjacent journal. The function ofthis sector and pointer is to determine when thebed-plateisapproximatelylevel. Anyfurther adjustment to secure a perfectleveling of the base-plate is effected through the leveling-screws abovedescribed. For rocking the bed-plate on its supporting-journals atoothsector a, depending from the bed-plate, is arranged in mesh with aworm f, journaled in a hanger f secured to one of the journalssupporting the bed-plate and provided with an operating-crank f. Forpermitting the bed-plate to swing about a vertical axis the base-supportg is rotatably carried in a frame g A'toothed sector f secured to thebasesupport, is arranged in mesh with a wormf journaled on the frame gand provided with an operating-crankf By the mechanism just describedadjustment of the bed-plate in every conceivable direction is providedfor, so that the device, as before pointed out, will be adaptable foruse either as a range-finder on vessels or for surveying purposes onland.

The operation of the device thus described when used as a range-finderin military operations upon the land is as follows: The frame g beingmounted upon any suitable support-such as a tripod, for instance-theworm-gearf is manipulated,by means of a crank f", in order to bring thepointer carried by the arm a upon the zero-point of the scale f Thebed-plate is then leveled by means of the leveling-screws g and thelevels a ("6 the fixed telescope being pointed in the general directionof the object the range of which it is desired to ascertain. This fixedtelescope is then pointed in a vertical line with said object by meansof the coarse adjustment of the worm-gear f and if the object be notupon a plane with the instrument the wormgear f is manipulated until theproper pitch of the fixed telescope is obtained. The crosshairs in thetelescope are then brought to bear exactly upon the object by means ofthe tangent-screw f. The movable telescope B is then manipulated, bymeans of the wheel carried by the rod 1), until its cross-hairs are alsobrought directly upon the object. At the same time with this movement ofthe movable telescope the sector-wheel O is operated to cause thepointer 61 to leave its zero position upon the dial 1) and traveltherearound in the direction of the movement of the hands of a clock,and when the object has been focused upon the cross-hairs of the movabletelescope the reading taken from the dial will give correctly the rangeof the object, these readings to be taken, as before explained, from thecircle indicated by the position of the pin 0 in the slot 0 From thisreading the elevation of the barrel of the gun may be calculated, at thesame time taking into consideration the angle of depression or elevationof the telescopes as read upon the scale f When used as a surveyorsinstrument, the manipulation of the leveling means will be similar tothat above described, and the method of locating a point at a givendistance heretofore described may be employed.

\Vhen used upon shipboard as a rangefinder, either the positive levelingmeans or the gravitating and freely-swinging leveling means may beutilized, or one of such means may be substituted for the other to suitthe prevailing conditions.

Having thus fully described the invention, what is claimed as new is- 1.In a device of the character described, the combination of a bed-plate,a fixed and a movable sighting device mounted thereon, an indicator, arod journaled on said bed-plate and provided with threads of differentpitch at its respective ends, and means operatively connecting saidthreaded ends to the movable sighting device and the indicator,substantially as described.

2. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator, a rod journaled on said bed-plate and provided with threadsof different pitch at its respective ends, means operatively connectingsaid threaded ends to the movable sighting device and the indicator, andmeans for securing positive action and preventing backlash in themechanism, substantially as described.

3. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator, a rod journaled on said bed-plate and provided with threadsof different pitch at its respective ends, means operatively c011-necting said threaded ends to the movable sighting device andtheindicator,andaspring' actuated Wheel arranged and constructed tosecure positive action and prevent backlash in the mechanism,substantially as described.

4-. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator provided with a dial and pointer, a plurality ofdifferently-graduated scales on said dial in position to be traversed bysaid pointer, an auxiliary pointer and auxiliary scale on the indicator,said auxiliary scale containing a number of divisions equal to thenumber of said dilferently-graduated scales, and so arranged that theposition of the aux iliary pointer will determine the particular scaleon which the reading of the indicatoris to be taken, and meansoperatively connecting the movable sighting device and the indicator,substantially as described.

5. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator provided with a dial and a pointer, a plurality ofdifferently-graduated concentric circles on said dial in position to betraversed by said pointer, an auxiliary pointer and auxiliary scale onthe indicator, said auxiliary scale containing a number of divisionsequal to the number of said differently-graduated circles, and soarranged that the position of the auxiliary pointer will determine theparticular graduated circle on which the reading of the indicator is tobe taken, and means operatively connecting the movable sighting deviceand the indicator, substantially as described.

6. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator provided with a dial and pointer, a

plurality of ditterently-graduated concentric circles on said dial inposition to be traversed by said pointer, an auxiliary pointer andauxiliary scale on the indicator, said auxiliary scale containing anumber of divisions equal to the number of said differently-graduatedcircles, and so arranged that the position of the auxiliary pointer willdetermine the particular graduated circle on which the reading of theindicator is to be taken, means operatively connecting the movablesighting device and the indicator, and means constructed and arranged toprevent backlash in the mechanism, substantially as described.

7. In a device of the character described,

the combination of a bed-pIate a fixed and a movable sighting devicemounted thereon, an indicator provided with a dial and pointer, atoothed sector arranged to operate said pointer, a rod jou rnaled onsaid bed-plate and provided with threads of different pitch at itsrespective ends, the threaded end of lesser vpitch operatively connectedto said movable sighting device and the threaded-end of greater pitcharranged in mesh with said toothed sector, and means constructed toprevent backlash in the mechanism, substantially as described.

8. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator provided with a dial and pointer,

' 'a toothed sector arranged to operate said pointer, a rod j ournaledon said bed-plate and provided with threads of different pitch at itsrespective ends, the threaded end of lesser pitch operatively connectedto said movable sighting device and the threaded end of greater pitcharranged to mesh with said toothed sector, and a spring-actuated wheelarranged and constructed to secure positive action and prevent backlashin the mechanism, substantially as described.

9. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, an

indicator provided with a dial and pointer, a

plurality of ditferentlygraduated scales on said dial in position to betraversed by said pointer, an auxiliary pointer and auxiliary scale onthe indicator, said auxiliary scale.

containing a number of divisions equal to the -number of saiddifferently-graduated scales, and so arranged that the position of theauxiliary pointer will determine the particular scale on which thereading of the indicator is to be taken, a toothed sector arranged inoperative connection with said first pointer and carrying said auxiliarypointer, a rod journaled on the bed-plate'and provided with threads ofdifferent pitch at its respective ends, the threaded end of lesser pitchoperatively connected to said movable sighting device and the threadedend of greater pitch arranged in mesh with said toothed sector,

and means constructed to prevent backlash in the mechanism,substantiallyas described;

10. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, an

indicator provided with a dial and pointer, a

plurality of differently-graduated scales on said dial in position to betraversed by said pointer, an auxiliary pointer and auxiliary scale onthe indicator, said auxiliary scale containing a number of divisionsequal to the number of said differently-graduated scales,

and so arranged that the position of the aux iliary pointer willdetermine the particular scale on which the reading of the indicator isto be taken, a toothed sector arranged in 0perative connection with saidfirst pointer and carrying said auxiliary pointer, a rod jour-- naled onthe bed-plate and provided with threads of different pitch at itsrespective ends, the threaded end of lesser pitch operatively connectedto said movable sighting device and the threaded end of. greater pitcharranged in mesh with said toothed sector, and a spring-actuated wheelarranged and constructed to secure positive action and prevent backlashin the mechanism, substantially as described.

the combination of a bed-plate, a fixed and a movable sighting devicemounted thereon, an indicator provided, with a dial and pointer, aplurality of differently-graduated scales on said dial in position to betraversed by said pointer, an auxiliary pointer and auxiliary scale onthe indicator, said auxiliary scale containing a number of divisionsequal to the- IIO I 12 5 11. In a device of the character described,

number of said differently-graduated scales, and so arranged that theposition of the auxiliary pointer will determine the particular scale onwhich the reading of the indicator is to be taken, a toothed sectorarranged in operative connection with said first pointer and carryingsaid auxiliary pointer, a rod journaled on the bedplate and providedwith threads of different pitch at its respective ends, the threaded endof lesser pitch operatively connected to said movable sighting deviceand the threaded end of greater pitch arranged in mesh with said toothedsector, a scale carried by said rod, a vernier adjacent said scale, andmeans constructed to prevent backlash in the mechanism, substantially asdescribed.

12. In a device of the character described,

the combination of a bed-plate, a fixed and a movable sighting devicemounted thereon, an indicator provided with a dial and pointer, aplurality of differently-graduated scales on said dial in position to betraversed by said pointer, an auxiliary pointer and auxiliary scale onthe indicator, said auxiliary scale containing a number of divisionsequal to the number of said differently-graduated scales, and soarranged that the position of the auxiliary pointer will determine theparticular scale on Which the reading of the indicator is to be taken, atoothed sector arranged in operative connection with said first pointerand carrying said auxiliary pointer, a rod journaled on the bed-plateand provided with threads of different pitch at its respective ends, thethreaded end of lesser pitch operatively connected to said movablesighting device and the threaded end of greater pitch arranged in meshwith said toothed sector, a scale adjustably supported on said rod,meansarranged to lock said scale in position on said rod, a vernier adjacentsaid scale, and means constructed to prevent backlash in the mechanism,substantially as described.

13. In a device of the character described, the combination of abed-plate, a fixed and a movable sighting device mounted thereon, anindicator provided with a dial and pointer, a plurality ofdifferentlygraduated scales on said dial in position to be traversed bysaid pointer, an auxiliary pointer and auxiliary scale on the indicator,said auxiliary scale containing a number of divisions equal to the maosenumber of said differently-graduated scales, and so arranged that theposition of the auxiliary pointer will determine the particular arrangedin mesh with said toothed sector, a

scale carried by said rod, a vernier adjacent said scale, and aspring-actuated Wheel arranged and constructed to secure positive actionand prevent backlash in the mechanism, 1 substantially as described.

14. In a device of the character described,

the combination of a bed-plate, afixed and a movable sighting devicemounted thereon, a

1 standard provided with a journal supporting said bed-plate, means forrocking the bedplate on its journal, comprising a worm car- 1 ried bysaid journal and an intermeshing Worm-wheel secured to the bed-plate, abase- 1 support for said standard, a frame on which said base'support isrotatably mounted, a

3 toothed sector secured to the base-support, 3 and an intermeshing Wormjournaled on said 1 frame, substantially as described.

15. In a device of the character described, the combinationof abed-plate, a fixed and a movable sighting device mounted thereon, astandard provided with a journal supporting ,said bed-plate, means forrocking the bedplate on its journal, comprising a Worm carried by saidjournal and an intermeshing worm-Wheelsecured to the bed-plate, agraduated sector carried by the bed-plate, a pointer secured to thejournal and arranged to traverse said graduated sector, a base-supportfor said standard, a frame on which said basesupport is rotatablymounted, a toothed sector secured to the base-support, and anintermeshing Worm journaled on said frame, substantially as described.

In testimony whereof I affix my signature in the presence of twosubscribing witnesses.

SARAH M. KERN. Witnesses:

ELLIS G. HUGHES, FRANK Mo'rrER.

